Antifolate-sulfa-antibiotic combinations are used to treat urinary tract infections, lower respiratory tract infections, and ear infections. They also have other uses, such as treating traveler's diarrhea. These medications work by blocking the production of folic acid in bacteria, which stops them from growing and multiplying. You can find these medications in both oral and injectable forms. Examples include sulfamethoxazole/trimethoprim (formerly under the brand name Sulfatrim) and sulfamethoxazole/trimethoprim (Bactrim, Septra).
